Protanopia Test (Red-Blind)
This Ishihara-style test screens for protanopia, the complete absence of red-sensitive (L) cones. If you have protanopia, you will have difficulty seeing the numbers hidden in these plates because the foreground and background colors fall along the red-green confusion axis.
Plate 1 of 10
What number do you see in the circle above?
Test Instructions
- Look at each colored circle
- Enter the number you see (if any)
- Take your time — there's no rush
- Make sure your screen brightness is normal
- Ensure good lighting conditions
Medical Disclaimer: This online test is a screening tool. While it can help identify potential color vision deficiencies, it is not a substitute for professional medical diagnosis. Screen brightness, lighting conditions, and display calibration can affect results.
What This Test Screens For
Protanopia is a form of dichromacy where the L-cones (long-wavelength, red-sensitive) are entirely absent. This test uses pseudoisochromatic plates designed along the red-green confusion axis. If you cannot distinguish the colored dots that form the hidden number from the background dots, it suggests a red-green color vision deficiency consistent with protanopia or protanomaly.
Limitations of This Test
This online screening cannot distinguish protanopia from protanomaly (red-weak) or from deutan-type deficiencies (deuteranopia, deuteranomaly). All red-green deficiencies produce similar patterns on Ishihara-style plates. A definitive diagnosis requires an anomaloscope test administered by an eye care professional. Screen calibration, brightness, and ambient lighting also affect accuracy.
What to Expect
You will see 10 circular plates filled with colored dots. Each plate contains a hidden number that people with normal color vision can read. Enter the number you see, or indicate that you see nothing. The test takes 2-3 minutes.
How Does This Protanopia Test Work?
Each plate uses colors carefully chosen along the protan/deutan confusion line. The number is rendered in warm tones (oranges, reds) against a background of cool-shifted tones (greens, olives) at matched luminance. A person with normal trichromatic vision can distinguish the hue difference and read the number. A person with protanopia lacks the L-cones needed to differentiate these hues, so the number blends into the background.
Understanding Protanopia
Protanopia affects approximately 1% of men and 0.01% of women. It is caused by the complete absence of functional L-cones due to mutations in the OPN1LW gene on the X chromosome. People with protanopia see the world primarily in blues and golds, with reds appearing very dark or nearly black. The condition also causes a characteristic brightness reduction for red, orange, and yellow-green colors.
Frequently Asked Questions
Can this test tell me if I have protanopia specifically?
This test screens for red-green color vision deficiency but cannot distinguish protanopia from protanomaly, deuteranopia, or deuteranomaly on its own. All four conditions cause difficulty reading Ishihara-style plates. For a specific diagnosis, you need an anomaloscope test from an eye care professional.
What score indicates protanopia?
If you correctly read fewer than 3 out of 10 plates, there is a strong indication of a red-green color vision deficiency. A score of 0-2 is consistent with protanopia or deuteranopia (complete absence of one cone type), while 3-7 may suggest the milder anomalous forms (protanomaly or deuteranomaly).
Is protanopia the same as being completely color blind?
No. Protanopia is specifically a red-blind condition where only the red-sensitive cones are absent. People with protanopia can still see blues, yellows, and many other colors. Complete color blindness (achromatopsia) is a much rarer condition in which all cone types are nonfunctional.
Learn more about this condition
Related Tests
Deuteranopia Test (Green-Blind)
This Ishihara-style test screens for deuteranopia, the complete absence of green-sensitive (M) cones. People with deuteranopia cannot distinguish the hidden numbers because the plate colors lie along the red-green confusion axis that their vision cannot resolve.
Protanomaly Test (Red-Weak)
This Ishihara-style test screens for protanomaly, a mild form of red-green color blindness where the red-sensitive (L) cones are present but spectrally shifted. People with protanomaly may have difficulty with some or all of these plates depending on the severity of their condition.
Red-Green Colorblind Test
This Ishihara-style test screens for all types of red-green color blindness, including protanopia, deuteranopia, protanomaly, and deuteranomaly. Red-green color deficiency is the most common form of color blindness, affecting approximately 8% of men and 0.4% of women worldwide.